N-aryl-4,5-diaminopyrazoles and dyes containing said compounds

ABSTRACT

N-Aryl-4,5-diaminopyrazole of formula (I) or a physiologically compatible salt thereof of an organic or inorganic acid 
                         
wherein
     R1 and R2 independently of each other denote a hydrogen atom, a straight-chain or branched C 1 –C 6 -alkyl group, a hydroxyl group, a straight-chain or branched C 1 –C 6 -monohydroxyalkyl group, a straight-chain or branched C 3 –C 6 -dihydroxyalkyl group, a straight-chain or branched C 1 –C 6 -alkoxy group, a straight-chain or branched C 1 –C 6 -hydroxyalkoxy group, a straight-chain or branched C 3 –C 6 -dihydroxyalkoxy group, an amino group, a C 1 –C 4 -monoalkylamino group, a di(C 1 –C 4 )-alkylamino group, a halogen atom, a difluoromethyl group or a trifluoromethyl group; Y stands for a nitrogen atom or a C-R3 group, wherein C is a carbon atom of the aromatic ring and R3 is a hydrogen atom, a halogen atom, a straight-chain or branched C 1 –C 6 -alkyl group, a straight-chain or branched C 1 –C 6 -hydroxyalkyl group, a straight-chain or branched C 1 –C 6 -alkoxy group, a straight-chain or branched C 2 -C 6 -hydroxyalkoxy group or a straight-chain or branched C 2 –C 6 -alkoxyalkoxy group; X denotes an acid radical and n has a value from 0 to 3; provided that when Y stands for a C-R3 group, at least one of the R1, R2 and R3 groups is different from hydrogen; as well as colorants for keratin fibers containing these compounds.

CROSS-REFERENCE

This is the U.S. National Stage of PCT/EP 03/05031, filed on May 14,2003 (International filing date), which claims the benefit of priorityof invention under 35 U.S.C. 119 and 365 (b) based on DE 102 54 506.5filed Nov., 22, 2002 in Germany.

BACKGROUND OF THE INVENTION

The present patent application has for an object new, aryl-substituted4,5-diaminopyrazoles and colorants for keratin fibers containing thesecompounds.

In the area of keratin fiber dyeing, particularly hair dyeing, oxidationdyes have attained substantial importance. In this case, the colorationis produced by reaction of certain developers with certain couplers inthe presence of an appropriate oxidant. Now as before, hair colorantsfor dyeing in the natural color shade range are particularly important.In addition, by combination of suitable oxidation dye precursors, it isalso possible to produce currently fashionable color shades. Currentlypopular are modified natural shades, for example brown shades withpronounced eggplant or copper tones and particularly brilliant redtones.

In addition to being able to produce color effects, oxidation dyesintended for use in treating human hair must meet many otherrequirements. Such dyes must be unobjectionable from a toxicological anddermatological standpoint, and the colorations achieved must show goodlight fastness, resistance to permanent waving, rubbing fastness,resistance to shampooing and sufficient resistance to perspiration.Moreover, by combination of suitable developers and couplers it must bepossible to produce a wide range of different color shades.

In the past, the red range, which as before is important, was providedpredominantly by use of 4-aminophenol as the developer. Because ofconcerns about the physiological compatibility of this substance,derivatives of pyridine and pyrimidine have also been used, but theywere unsatisfactory from a coloring standpoint. A significantimprovement in color stability in the red range was achieved for thefirst time by replacing p-aminophenol with 4,5-diaminopyrazolesdescribed in EP-A 0 375 977. Moreover, DE-A 101 09 806 disclosescombinations of substituted pyrazolones and 4,5-diaminopyrazoles tocreate yellow to orange shades.

Whereas most oxidation dyes hardly show any weaknesses on undamagedhair, major differences can arise on damaged hair. Hence, thehairdresser knows from his everyday practice the problem that dyes arenot absorbed uniformly by the hair to be dyed. Whereas the hair rootsare usually intact, the hair tips in the course of time show damagecaused by the effect of weather factors and frequent washing and combingand which increases from the roots to the tips of the hair. When suchhair is dyed, then because of the nonuniform hair structure betweenroots and tips, the coloring results can be nonuniform. Another problemlies in that during washing the dyes are more strongly washed out fromthe damaged hair regions than from the undamaged ones, which after a fewhair washings can become gradually more noticeable depending on thedegree of hair damage. In particular, the customer also notices thisbecause the hair tips look dull.

SUMMARY OF THE INVENTION

A need thus continued to exist for dyes that, on the one hand, wouldgive highly brilliant color shades and, on the other, have markedlyimproved color resistance to shampooing on hair varying greatly inquality, particularly on hair damaged by permanent waving or bleaching.Moreover, the color shades produced should not loose their brillianceeven after several hair washings.

We have now found that the N-aryl-4,5-diaminopyrazoles of formula (I)described in the following meet the aforesaid requirements inoutstanding manner in that besides heretofore unequaled color brillianceand color depth these new dyes provide markedly improved colorstability.

The present invention therefore has for an objectN-aryl-4,5-diaminopyrazoles of formula (I) or their physiologicallycompatible salts of organic or inorganic acids

wherein

-   R1 and R2 independently of each other denote a hydrogen atom, a    straight-chain or branched C₁–C₆-alkyl group, a hydroxyl group, a    straight-chain or branched C₁–C₆-monohydroxyalkyl group, a    straight-chain or branched C₃–C₆-dihydroxyalkyl group, a    straight-chain or branched C₁–C₆-alkoxy group, a straight-chain or    branched C₁–C₆-hydroxyalkoxy group, a straight-chain or branched    C₃–C₆-dihydroxyalkoxy group, an amino group, a C₁–C₄-monoalkylamino    group, a di(C₁–C₄)-alkylamino group, a C₁–C₄-aminoalkyl group, a    halogen atom (F, Cl, Br, I), a difluoromethyl group or a    trifluoromethyl group;-   Y stands for a nitrogen atom, or a C-R3 group, wherein C is a carbon    atom of the aromatic ring and R3 is a hydrogen atom, a halogen atom    (F, Cl, Br, I), a straight-chain or branched C₁–C₆-alkyl group, a    straight-chain or branched C₁–C₆-hydroxyalkyl group, a    straight-chain or branched C₁–C₆-alkoxy group, a straight-chain or    branched C₂–C₆-hydroxyalkoxy group or a straight-chain or branched    C₂–C₆-alkoxyalkoxy group;-   X denotes an acid radical and n has a value from 0 to 3; provided    that when Y stands for a C-R3 group, at least one of the R1, R2 and    R3 groups is different from hydrogen.

Preferred compounds of formula (I) are those wherein:

-   R1 and R2 independently of each other denote hydrogen, a methyl    group, an ethyl group, an isopropyl group, an amino group or a    methoxy group; and Y stands for a C—H group, a C—Cl group, a    C-methyl group or a C-ethyl group and, in particular, a nitrogen    atom, and when Y stands for a C—H group at least one of the R1 and    R2 groups is not hydrogen.

Particularly preferred are the following compounds of formula (I):

-   1-(2-methylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-a)

-   1-(3-methylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-b)

-   1-(4-methylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-c)

-   1-(2,4-dimethylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-d)

-   1-(2,5-dimethylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-e)

-   1-(2-ethylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-f)

-   1-(4-isopropylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-g)

-   1-(4-methoxylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-h)

-   1-(4-aminophenyl)-4,5-diamino-1H-pyrazole sulfate (1:1) (I-i)

-   1-(4-chlorophenyl)-4,5-diamino-1H-pyrazole sulfate (2:1) (I-k)

-   1-(2-pyridinyl)-4,5-diamino-1H-pyrazole dihydrochloride (I-l)

The compounds of formula (I) can be prepared by methods analogous to theknown ones, for example by cyclization of an arylhydrazine withmethoxyacrylonitrile, ethoxyacrylonitrile or chloroacrylonitrile, orelse, in ideal fashion, with dimethylaminoacrylonitrile according to thegeneral method according to Scheme 1:

In certain cases, however, it may be advantageous from a preparativestandpoint to subject the 5-aminopyrazoles to reaction with a diazoniumsalt, as shown in Scheme 2, to form an azo dye, then cleaving the dyeand isolating the compound of formula (I).

Eminently suited for the preparation of the intermediate azo compoundsare aniline, anilines substituted with one or more C₁–C₆-groups oranisidines, sulfanilic acid, metanilic acid, orthanilic acid,p-aminobenzoic acid, m-aminobenzoic acid and 5-aminoisophthalic acid.Particularly preferred among these compounds are sulfanilic acid,p-aminobenzoic acid and 5-aminoisophthalic acid.

For better handling, the N-aryl-4,5-diaminopyrazoles of formula (I) ofthe invention are not isolated in the form of the free bases butpreferably in the form of the corresponding salts which are lesssensitive to oxidation. The acids used can be inorganic or organicacids, and preferably citric acid, tartaric acid, phosphoric acid andespecially hydrochloric acid or sulfuric acid.

The compounds of formula (I) are eminently suited as dye precursors inthe oxidative system for dyeing keratin fibers. Although these compoundsare suitable particularly for use in dyeing keratin fibers, for examplewool, silk or hair, particularly human hair, these compounds can inprinciple also be used to dye other natural or synthetic fibers, forexample cotton or nylon 6,6.

Another object of the present invention is therefore a colorant foroxidative dyeing of keratin fibers, for example wool, furs, feathers orhair and particularly human hair, characterized in that it contains atleast one N-aryl-4,5-diaminopyrazole of general formula (I) or aphysiologically compatible salt thereof.

The colorant of the invention contains the N-aryl-4,5-diaminopyrazolesof formula (I) in an amount from about 0.005 to 20 weight percent,preferably in an amount from about 0.01 to 10 weight percent andparticularly from 0.1 to 6 weight percent.

The compounds of formula (I) can be used alone or in combination withknown developers and/or couplers commonly used in systems for oxidativedyeing of fibrous materials.

Suitable couplers are, in particular, N-(3-dimethylaminophenyl)urea,2,6-diaminopyridine, 2-amino-4-[(2-hydroxyethyl)amino]anisole,2,4-diamino-1-fluoro-5-methylbenzene, 2,4-diamino-1-methoxy-5-methylbenzene, 2,4-diamino-1-ethoxy-5-methylbenzene,2,4-diamino-1-(2-hydroxyethoxy)-5-methyl-benzene,2,4-di[(2-hydroxyethyl)amino]-1,5-dimethoxybenzene,2,3-diamino-6-methoxypyridine,3-amino-6-methoxy-2-(methylamino)pyridine,2,6-diamino-3,5-dimethoxypyridine, 3,5-diamino-2,6-di-methoxypyridine,1,3-diaminobenzene, 2,4-diamino-1-(2-hydroxyethoxy)benzene,2,4-diamino-1-(3-hydroxypropoxy)benzene,2,4-diamino-1-(3-methoxypropoxy)benzene,1-(2-aminoethoxy)-2,4-diaminobenzene,2-amino-1-(2-hydroxyethoxy)₄-methylaminobenzene,2,4-diaminophenoxyacetic acid, 3-[di(2-hydroxyethyl)amino]aniline,4-amino-2-di[(2-hydroxyethyl)amino]-1-ethoxybenzene,5-methyl-2-(1-methylethyl)phenol, 3-[(2-hydroxyethyl)amino]aniline,3-[(2-aminoethyl)amino]aniline, 1,3-di(2,4-di-aminophenoxy)propane,di(2,4-diaminophenoxy)methane, 1,3-diamino-2,4-dimethoxybenzene,2,6-bis(2-hydroxyethyl)aminotoluene, 4-hydroxyindole,3-dimethylaminophenol, 3-diethylaminophenol, 5-amino-2-methylphenol,5-amino-4-fluoro-2-methylphenol, 5-amino-4-methoxy-2-methylphenol,5-amino-4-ethoxy-2-methylphenol, 3-amino-2,4-dichlorophenol,5-amino-2,4-dichlorophenol, 3-amino-2-methylphenol,3-amino-2-chloro-6-methylphenol, 3-aminophenol,2-[(3-hydroxyphenyl)amino]acetamide,5-[(2-hydroxyethyl)amino]-2-methylphenol,3-[(2-hydroxyethyl)amino]phenol, 3-[(2-methoxyethyl)amino]phenol,5-amino-2-ethylphenol, 2-(4-amino-2-hydroxyphenoxy)ethanol,5-[(3-hydroxypropyl)amino]-2-methylphenol,3-[(2,3-dihydroxypropyl)amino]-2-methylphenol,3-[(2-hydroxyethyl)amino]-2-methylphenol, 2-amino-3-hydroxypyridine,5-amino-4-chloro-2-methylphenol, 1-naphthol, 1,5-dihydroxynaphthalene,1,7-dihydroxynaphthalene, 2,3-dihydroxynaphthalene,2,7-dihydroxynaphthalene, 2-methyl-1-naphthol acetate,1,3-dihydroxybenzene, 1-chloro-2,4-dihydroxy-benzene,2-chloro-1,3-dihydroxybenzene,1,2-dichloro-3,5-dihydroxy-4-methylbenzene,1,5-dichloro-2,4-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene,1,3-dihydroxy-2,4-dimethylbenzene, 3,4-methylenedioxyphenol,3,4-methylenedioxyaniline, 5-[(2-hydroxyethyl)amino]-1,3-benzodioxole,6-bromo-1-hydroxy-3,4-methylenedioxybenzene, 3,4-diaminobenzoic acid,3,4-dihydro-6-hydroxy-1,4-(2H)-benzoxazine,6-amino-3,4-dihydro-1,4(2H)benzoxazine, 3-methyl-1-phenyl-5-pyrazolone,5,6-dihydroxyindole, 5,6-dihydroxyindoline, 4-hydroxyindole,5-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole and 2,3-indolinedioneor the salts thereof.

To prepare the natural-like shades and fashionable red shades, it isparticularly advantageous to use the compounds of formula (I) incombination with additional developers. Suitable developers arep-phenylenediamines, p-aminophenols and other 4,5-diaminopyrazoles orthe salts thereof.

Particularly noteworthy are the following developers:

1,4-diaminobenzene (p-phenylenediamine), 1,4-diamino-2-methylbenzene(p-toluylene-diamine), 1,4-diamino-2,6-dimethylbenzene,1,4-diamino-2,5-dimethylbenzene, 1,4-diamino-2,3-dimethylbenzene,2-chloro-1,4-diaminobenzene, 4-phenylaminoaniline,4-dimethylaminoaniline, 4-diethylaminoaniline,4-[di(2-hydroxyethyl)amino]anine, 4-[(2-methoxyethyl)amino]aniline,4-[(3-hydroxypropyl)amino]aniline,1,4-diamino-2-(2-hydroxyethyl)benzene,1,4-diamino-2-(1-hydroxyethyl)benzene,1,4-diamino-2-(1-methylethyl)benzene,1,4-diamino-2-(1-methylethyl)benzene,1,3-bis[(4-aminophenyl)-(2-hydroxy-ethyl)amino]-2-propanol,1,8-bis-(2,5-diaminophenoxy)-3,6-dioxaoctane, 4-aminophenol,4-amino-3-methylphenol, 4-methylaminophenol,4-amino-2-(aminomethyl)phenol,4-amino-2-[(2-hydroxy-ethyl)amino]methylphenol,4-amino-2-(methoxymethyl)phenol, 4-amino-2-(2-hydroxyethyl)phenol,5-aminosalicylic acid, 2,5-diaminopyridine, 2,4,5,6-tetraminopyrimidine,2,5,6-triamino-4-(1H)-pyrimidone,4,5-diamino-1-(2-hydroxyethyl)-1H-pyrazole,4,5-diamino-1-(1-methylethyl)-1H-pyrazole,4,5-diamino-1-(4-methylbenzyl)-1H-pyrazole,1-(4-chlorobenzyl)-4,5-diamino-1H-pyrazole,4,5-diamino-1-methyl-1H-pyrazole,4,5-diamino-3-methyl-1-phenyl-1H-pyrazole,4,5-diamino-1-methyl-1H-pyrazole, 4,5-diamino-1-pentyl-1H-pyrazole,4,5-diamino-1-benzyl-1H-pyrazole,4,5-diamino-1-(4-methoxybenzyl)-1H-pyrazole,4,5-diamino-1-(2-hydroxyethyl)-3-methyl-1H-pyrazole, 2-aminophenol,2-amino-6-methylphenol and 2-amino-5-methyl-phenol or the salts thereof.

The aforesaid developers and couplers can be used individually or inadmixture with one another, the aforesaid known developers and couplersbeing contained in the colorant of the invention in a total amount fromabout 0.01 to 20 weight percent and preferably from about 0.2 to 6weight percent.

Moreover, the colorant of the invention can contain other dyecomponents, for example 4-(2,5-diaminobenzylamino)aniline or3-(2,5-diaminobenzylamino)aniline, as well as common natural dyes, dyesidentical to natural ones, or synthetic direct dyes from the groupconsisting of anionic (acid) and cationic (basic) dyes, triarylmethanedyes, nitro dyes, disperse dyes and azo dyes, for example natural dyessuch as indigo or henna, triphenylmethane dyes such as4-[(4′-aminophenyl)-(4′-imino-2′,5″-cyclohexadien-1″-ylidene)methyl]-2-methylaminobenzenemonohydrochloride (C.I. 42510), and4-[(4′-amino-3′-methylphenyl)-(4″-imino-3″-methyl-2′,5″-cyclohexadien-1″-ylidene)methyl]-2-methylamino-benzenemonohydrochloride (C.I. 42520), aromatic nitro dyes such as4-(2′-hydroxyethyl)-aminonitrotoluene, 2-amino-4,6-dinitrophenol,2-amino-5-(2′-hydroxyethyl)aminonitrobenzene,2-chloro-6-(ethylamino)₄-nitrophenol,4-chloro-N-(2-hydroxyethyl)-2-nitroaniline,5-chloro-2-hydroxy-4-niroaniline, 2-amino-4-chloro-6-nitrophenol and1-[(2′-ureidoethyl)amino-4-nitrobenzene, azo dyes such as sodium6-[(4′-aminophenyl)azo]-5-hydroxynaphthalene-1-sulfonate (C.I. 14805)and disperse dyes, for example 1,5-diaminoanthraquinone and1,4,5,8-tetraminoanthraquinone.

The colorant of the invention contains the direct dyes at a totalconcentration from about 0.1 to 10 weight percent and preferably fromabout 0.1 to 5 weight percent.

Naturally, the dyes, provided they are bases, can also be used in theform of their physiologically compatible salts of organic or inorganicacids, for example hydrochloric acid or sulfuric acid, or—if theycontain aromatic OH— groups—in the form of salts of bases, for exampleas alkali metal phenoxides.

For dyeing, the abovesaid combinations of compounds of formula (I) ofthe invention with oxidative hair dye precursors and/or direct dyes areapplied in an appropriate dye carrier composition.

Moreover, the colorants can also contain other common additives, forexample antioxidants such as ascorbic acid, thioglycolic acid or sodiumsulfite, as well as perfume oils, penetrants, buffering systems,complexing agents, preservatives, wetting agents, emulsifiers,thickeners and hair-care agents.

The colorant of the invention can be formulated, for example, as asolution, particularly an aqueous or aqueous-alcoholic solution, or as apaste, cream, gel, emulsion or aerosol preparation. Such a colorantpreparation consists of a mixture of dye components and additivescommonly used for such preparations.

Common additives to solutions, creams, emulsions or gels are, forexample, solvents such as water, lower aliphatic alcohols, for exampleethanol, propanol or isopropanol, glycerol or glycols such as1,2-propylene glycol; moreover wetting agents or emulsifiers from theclasses of anionic, cationic, amphoteric or nonionic surface-activesubstances such as, for example, the fatty alcohol sulfates, ethoxylatedfatty alcohol sulfates, alkylsulfonates, alkylbenzenesulfonates,alkyltrimethylammonium salts, alkylbetaines, ethoxylated fatty alcohols,ethoxylated nonylphenols, fatty alkanolamides and ethoxylated fattyesters, furthermore thickeners such as the higher fatty alcohols,starch, cellulose derivatives, petrolatum, paraffin oil and fatty acids;moreover hair-care agents such as cationic resins, lanolin derivatives,cholesterol, pantothenic acid and betaine. The said constituents areused in amounts commonly employed for such purposes, for example thewetting agents and emulsifiers at a concentration from about 0.5 to 30weight percent, the thickeners in an amount from about 0.1 to 30 weightpercent and the hair-care agents at a concentration from about 0.1 to 5weight percent.

Depending on the composition, the colorant of the invention can beweakly acidic, neutral or alkaline. In particular, it has a pH from 6 to11.5, the adjustment to a basic value preferably being achieved withammonia or an organic amine, for example monoethanolamine ortriethanolamine, or an amino acid, or an inorganic base such as sodiumhydroxide or potassium hydroxide. It is also possible to usecombinations of the aforesaid compounds, particularly a combination ofammonia and monoethanolamine. For pH adjustment in the acidic range, aninorganic or organic acid, for example phosphoric acid, acetic acid,citric acid or tartaric acid, can be used.

For use in oxidative hair dyeing, the afore-described colorant (pH=6 to11.5) is mixed with an oxidant (pH=2 to 6.5) just before use. The pH ofthe ready-for-use hair colorant depends on the amount of alkali in thedye carrier and of acid in the oxidant, as well as on the mixing ratio.Depending on the composition, the ready-for-use colorant can be weaklyacidic, neutral or alkaline and have a pH from about 3 to 11 andpreferably from about 5 to 10.

Suitable oxidants for developing the hair coloration are mainly hydrogenperoxide or the compounds of addition thereof to urea, melamine, sodiumborate or sodium carbonate in the form of a 3 to 12%, preferably 6%aqueous solution. Atmospheric oxygen can also be used. Based on a 6%concentration of free hydrogen peroxide in the oxidant, the weight ratioof hair colorant to oxidant is from about 5:1 to 1:2 and preferably 1:1.Larger amounts of oxidant are used primarily at higher dyeconcentrations in the hair colorant or when more pronounced hairbleaching is wanted at the same time.

This mixture is applied to the hair in an amount sufficient for the hairtreatment, in general from about 60 to 200 grams depending on thefullness of the hair, and the mixture is allowed to act on the hair at15 to 50° C. for about 10 to 45 minutes and preferably 30 minutes, afterwhich the hair is rinsed with water and dried. Optionally, followingthis rinsing the hair is washed with a shampoo and optionallypost-rinsed with a weak organic acid, for example citric acid ortartaric acid. The hair is then dried.

The colorant of the invention containing an N-aryl-4,5-diaminopyrazoleof formula (I) gives hair colorations of excellent color stability,particularly in terms of light fastness, wash fastness and rubbingfastness. As far as the coloring properties are concerned, depending onthe kind and composition of the dye components, the colorants of theinvention provide a wide range of different color shades particularly inthe range of the fashionable red shades. The shades show unusual colorintensity and brilliance. The very good coloring properties of thecolorants of the present patent application manifest themselvesparticularly in that these colorants provide uniform and durablecolorations even on hair previously damaged to different degrees.

The following examples will explain in greater detail the subject matterof the invention without limiting its scope.

EXAMPLES Example 1 Preparation of1-(4-methoxyphenyl)-4,5-diamino-1H-pyrazole dihydrochloride

Step 1.1: 5-Amino-1-(4-methoxyphenyl)-1H-pyrazole

20.43 g (117 mmol) of 4-methoxyphenylhydrazine hydrochloride and 12.5 g(130 mmol) of 3-dimethylaminoacrylonitrile in 200 mL of methanol wereheated at reflux for 2 hours. The reaction mixture was allowed to cooland was then poured onto 600 mL of ice water upon which the5-amino-1-(4-methoxyphenyl)pyrazole [sic] precipitated. Filtration anddrying gave 17.4 g (92 mmol, 79% of the theoretical) of a purplishproduct.

¹H-NMR (DMSO-d₆): δ=3.60 ppm (d, ⁴J_(HH)=7.0 Hz, 2H); 3.67 ppm (s, 3H);6.81 ppm (d, ³J_(HH)=11.0 Hz, 2H); 6.85 ppm (d, ³J_(HH)=11.0 Hz, 2H);7.00 ppm (t, ⁴J_(HH)=7.0 Hz, 1H); 9.90 ppm (s, 1H).

Step 1.2: 5-Amino-1-(4-methoxyphenyl)₄-nitrosopyrazole hydrochloride

17.4 g (92 mmol) of 5-amino-1-(4-methoxyphenyl)pyrazole [sic] from Step1.1 was dissolved in 200 mL of tetrahydrofuran, 52.4 g of 32%hydrochloric acid was added, and the mixture was cooled to 0–5° C. Then11.8 g (101 mmol) of isopentyl nitrite was added dropwise with agitationso that the temperature did not exceed 5° C. Gradually, a brownishprecipitate formed which after an additional 2-hour agitation period inan ice bath was removed by suction filtration and washed with a smallamount of tetrahydrofuran. Drying gave 16.4 g (64 mmol, 70% of thetheoretical) of 5-amino-1-(4-methoxyphenyl)-4-nitrosopyrazolehydrochloride.

¹H-NMR (DMSO-d₆): δ=3.83 ppm (s, 3H); 7.0 ppm (s broad, 3H); 7.11 ppm(d, ³J_(HH)=15 Hz, 2H; 7.45 ppm (d, ³J_(HH)=15 Hz, 2H); 8.75 ppm (s,1H).

Step 1.3: 1-(4-Methoxyphenyl)-4,5-diamino-1H-pyrazole dihydrochloride

8.0 g (31 mmol) of 5-amino-1-(4-methoxyphenyl)₄-nitrosopyrazolehydrochloride from Step 1.2 in 200 mL of ethanol was hydrogenated for 6hours on 0.8 g of Pd/C (10%) at 8 bar of hydrogen pressure. The catalystwas filtered off, and the reaction mixture was concentrated to a totalvolume of about 30 mL. After the addition of 40 mL of 3-molar ethanolichydrochloric acid and agitation in an ice bath, the productcrystallized. Suction filtration and washing with 50 mL of ethyl acetategave 7.4 g (27 mmol), 86% of the theoretical) of1-(4-methoxyphenyl)-4,5-diamino-1H-pyrazole dihydrochloride.

¹H-NMR (DMSO-d₆): δ=3.82 ppm (s, 3H; 5.29 ppm (s broad, 3H); 7.07 ppm(d, ³J_(HH)=15 Hz, 2H); 7.44 ppm (d, ³J_(HH)=15 Hz, 2H); 7.46 ppm (s,1H); 10.04 ppm (s broad, 3H).

Example 2 Preparation of 1-(4-isopropylphenyl)-4,5-diamino-1H-pyrazoledihydrochloride

Step 2.1: 5-Amino-1-(4 isopropylphenyl)-1H-pyrazole

15.7 g (84 mmol) of 4-isopropylphenylhydrazine hydrochloride and 8.9 g(93 mmol) of 3-dimethylaminoacrylonitrile in 150 mL were heated atreflux for 3 hours. The reaction mixture was then cooled and poured into600 mL of ice water which caused 5-amino-1-(4-isopropylphenyl)pyrazole[sic] to precipitate. Filtering, washing with 100 mL of water and dryinggave 14.9 g (74 mmol, 88% of the theoretical) of a beige product.

¹H-NMR (DMSO-d₆): δ=1.17 ppm (d, ³J_(HH)=11.3 Hz, 6H); 2.78 ppm (h,³J_(HH)=11.3 Hz, 1H); 6.88 ppm (d, ³J_(HH)=14.1 HZ, 2H); 7.05 ppm (s,I); 7.07 ppm (d, ³J_(HH)=14.1 Hz, 2H); 10.02 ppm (s, 1H).

Step 2.2: 5-amino-1-(4-isopropylphenyl)₄-nitroso-1H-pyrazolehydrochloride

14.9 g (74 mmol) of 5-amino-1-(4-isopropylphenyl)pyrazole [sic] fromStep 2.1 was dissolved in 130 mL of tetrahydrofuran. 42.2 g of 32%hydrochloric acid was added, and the reaction mixture was cooled to 0 to5° C. Then, 9.5 g (81 mmol) of isopentyl nitrite was added dropwise withagitation so that the temperature did not exceed 5° C. Gradually, ayellowish precipitate formed which after an additional 1.5-houragitation period in an ice bath was removed by suction filtration andwashed with a small amount of tetrahydrofuran. Drying gave 12.3 g (46.1mmol, 62% of the theoretical) of5-amino-1-(4-isopropylphenyl)₄-nitroso-1H-pyrazole hydrochloride.

¹H-NMR (DMSO-d₆): δ=1.25 ppm (d, ³J_(HH)=11.7 Hz, 6H); 2.99 ppm (h,³J_(HH)=11.7 Hz, 1H); 7.45 ppm (m centered, 4H); 8.77 ppm (s, 1H).

Step 2.3: 4,5-Diamino]-(4-isopropylphenyl)-1H-pyrazole dihydrochloride

6.0 g (22.5 mmol) of 5-amino-1-(4-isopropylphenyl)-4-nitroso-1H-pyrazolehydrochloride from Step 2.2 in 150 mL of ethanol was hydrogenated for 6hours on 0.6 g of Pd/C (10%) at 8 bar of hydrogen pressure. The catalystwas filtered off, and the filtrate was concentrated to a total volume ofabout 20 mL. After the addition of 40 mL of a 3-molar ethanolichydrochloric acid solution and agitation in an ice bath, the productcrystallized out. Suction filtration and washing with 50 mL of ethylacetate gave 5 g (17.2 mmol, 77% of the theoretical) of4,5-diamino-1-(4-isopropylphenyl)-1H-pyrazole dihydrochloride as acolorless product.

¹H-NMR (DMSO-d₆): δ=1.24 ppm (d, ³J_(HH)=11 Hz, 6H); 2.97 ppm (h,³J_(HH)=11 Hz, 1H); 7.39 ppm (d, ³J_(HH)=14.2 Hz, 2H); 7.47 ppm (h,³J_(HH)=14.2 Hz, 2H); 7.49 ppm (s, 1H); 7.61 ppm (s broad, 34); 10.15ppm (s broad, 3H).

The N-aryl-4,5-diaminopyrazoles described in the following Examples 3 to9 can be prepared in a manner analogous to that of Examples 1 and 2 byusing the corresponding hydrazines.

Example 3 1-(2-Methylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride

¹H-NMR (DMSO-d₆): δ=2.06 ppm (s, 3H); 6.36 ppm (s broad, 3H); 7.26 ppm(d, ³J_(HH)=12.8 Hz, 1H); 7.25-7.40 ppm (m, 3H); 7.49 ppm (s, 1H); 10.09ppm (s broad, 3H).

Example 4 1-(3-Methylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride

¹H-NMR (DMSO-d₆): δ=2.38 ppm (s, 3H); 7.00 ppm (s broad, 3H); 7.21 ppm(d, ³J_(HH)=12.2 Hz, 1H); 7.30-7.45 ppm (m, 3H); 7.49 ppm (s, 1H); 10.14ppm (s broad, 3H).

Example 5 1-(4-Methylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride

¹H-NMR (DMSO-d₆): δ=2.37 ppm (s, 3H); 6.69 ppm (s broad, 3H); 7.32 ppm(d, ³J_(HH)=13 8 Hz, 2H); 7.43 ppm d, ³J_(HH)=13.8 Hz, 2H); 7.47 ppm (s,1H); 10.12 ppm (s broad, 3H).

Example 6 1-(2,4-Methylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride

¹H-NMR (DMSO-d₆): δ=1.99 ppm (s, 3H); 2.32 ppm (s, 3H); 4.49 ppm (sbroad, 3H); 7.14 ppm (m centered, 2H); 7.22 ppm (s, if); 7.49 ppm (s,1H); 10.04 ppm (s broad, 3H).

Example 7 1-(2,5-Methylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride

¹H-NMR (DMSO-d₆): δ=2.00 ppm (s, 3H); 2.32 ppm (s, 3H); 4.49 ppm (sbroad, 3H); 7.07 ppm (s, 1H); 7.10-7.30 ppm (m, 2H); 7.46 ppm (s, 1H);10.11 ppm (s broad, 3H).

Example 8 4,5-Diamino-1-(2-ethylphenyl)-1H-pyrazole dihydrochloride

Elemental analysis: C₁₁H₁₄N₄×2 HCl×0.5H₂O (mol. wt. =284.19)

C H N Cl Calculated: 46.5% 6.03% 19.71% 24.95% Found: 47.0% 5.90% 19.80%25.07%

Example 9 1-(2-Pyridinyl)-4,5-diamino-1H-pyrazole dihydrochloride

¹H-NMR (DMSO-d₆): δ=7.35 ppm (m, 1H); 7.57 ppm (s, 1H); 7.87 ppm (d,³J_(HH)=12 Hz, 1H); 8.45 ppm (m, 1H); 10.04 ppm (s broad, 3H).

Elemental analysis: C₈H₉N₅×2 HCl (Mol. wt. =248.11)

C H N Cl Calculated: 38.73% 4.47% 28.23% 28.58% Found:  39.1%  4.3% 27.7%  28.4%

Example 10 1-(4-Chlorophenyl)-4,5-diamino-1H-pyrazole hemisulfate

Step 10.1: 5-Amino-1-(4-chlorophenyl)pyrazole

21.5 g (0.12 mol) of 4-chlorophenylhydrazine hydrochloride was suspendedin 150 mL of methanol, 5 mL of concentrated hydrochloric acid was added,and the mixture was heated at reflux, which gave a clear, yellow-brownsolution. To this solution was added dropwise 11.5 g (0.12 mol) ofdimethylaminoacrylonitrile over a period of 30 minutes. After 1.5 h atreflux, most of the solvent was removed under vacuum. The remainingresidue was taken up in 40 mL of dimethylformamide, and 9 mL ofconcentrated ammonia solution was added at room temperature. Theresulting white precipitate was filtered off and discarded. The clearfiltrate was used in Step 10.2 without further purification.

Step 10.2: 5-Amino-1-(4-chlorophenyl)-4-(4-sulfophenylazo)pyrazole

20.8 g (0.12 mol) of sulfanilic acid was diazotized and to the mixturewas then added with continuing ice cooling 18.9 g (0.23 mol) of sodiumacetate. The dimethylformamide solution from Step 10.1 was addeddropwise over a period of 30 minutes. During the addition, thesuspension changed color from gray to yellow-brown. The mixture wasallowed to agitate an additional 2 h at 5° C. after which it was allowedto stand overnight at room temperature. The next day, the reactionproduct was filtered off, the moist filter cake was suspended in 350 mLof dimethylformamide and heated to about 80° C. Then, first 19.2 g (0.19mol) of triethylamine and then 100 mL of water were added to dissolvethe intermediate product. The clear solution was allowed to agitate inthe presence of 3.5 g of activated carbon for about 15 minutes and wasthen filtered warm. The residue on the filter was washed with a smallamount of water. To the still warm filtrate was then added 17.8 mL (0.21mol) of concentrated hydrochloric acid, and the resulting yellowsuspension was cooled to 0 to 5° C. The precipitated product was removedby suction filtration and washed with 15-mL portions of isopropanol. Theresidue was dried at 60° C. This gave 23.8 g (63% of the theoretical) of5-amino-1-(4-chlorophenyl)-4-(4-sulfophenylazo)pyrazole. Melting point;260° C. (decomp.).

Step 10.3; 1-(4-Chlorophenyl)-4,5-diamino-1H-pyrazole hemisulfate

20 g (52.9 mmol) of5-amino-1-(4-chlorophenyl)-4-(4-sulfophenylazo)pyrazole from Step 10.2in 200 mL of methanol and 20 mL of water was hydrogenated for 6 hours on2 g of moist Raney nickel (water content: 50%) at 60° C. and at ahydrogen pressure of 2 bar. The catalyst was removed under a nitrogenatmosphere. Amberlyst A 26 ion exchanger (basic form; about 44 g=64mmol) was then gradually added to the filtrate with agitation until nosulfanilic acid could be detected in the filtrate by thin-layerchromatography. The ion exchanger was filtered off and washed 4 timeswith 50-mL portions of methanol. The filtrate was introduced directlyinto a previously prepared solution of 3 g (30 mmol) of sulfuric acidand 20 mL of methanol, which caused the formation of a yellowish,coarsely crystalline precipitate. The precipitate was filtered off,washed with a small amount of Isopropanol and dried at 60° C. undervacuum. This gave 8.9 g (35 mmol, 65% of the theoretical) of crudeproduct.

For purification, the 8.9 g (35 mmol) of crude product was dissolved ina mixture of 90 mL of isopropanol and 5 mL (40 mmol) of triethylamine.The clear, light-red filtrate was then allowed to agitate with 1 g ofactivated carbon at about 30° C. for about 15 minutes and was thenfiltered into a solution of 1 mL (20 mmol) of concentrated sulfuric acidand 100 mL of isopropanol. The resulting thick suspension was cooled inan ice bath, allowed to agitate for an additional 30 minutes and thenfiltered. The precipitate was washed with a small amount of isopropanoland dried at 60° C. under vacuum. Yield: 8.5 g (95.3% of thetheoretical).

8.4 g (32 mmol) of the product thus obtained was dissolved in 40 mL ofwater and 2 mL of isopropanol by allowing the mixture to agitate for 30min at room temperature. The solid was filtered off and washed firstwith a small amount of cold water and then several times with a total of30 mL of isopropanol, until the washings became colorless. Drying at 60°C. under vacuum gave 7.63 g (91.28% of the theoretical) of1-(4-chlorophenyl)-4,5-diamino-1H-pyrazole hemisulfate; melting point:227.3° C. (decomp.).

¹H-NMR (DMSO-d₆): δ=6.90 ppm (s very broad, 6H); 7.32 ppm (s, 1H); 7.54ppm (d, ³J_(HH)=14.8 Hz, 2H); 7.66 ppm (d, ³J_(HH)=14.8 Hz, 2H).

Elemental analysis: C₉H₉ClN₄×0.5H₂SO₄ (mol. wt. =257.65)

C H N S Cl Calculated: 41.96% 3.91% 21.75% 6.22% 13.75% Found: 42.08%3.64% 21.80% 6.14% 13.65%

Example 11 1-(4-Aminophenyl)-4,5-diamino-1H-pyrazole sulfate

Step 11.1: 5-Amino-1-(4-nitrophenyl)-1H-pyrazole

7.65 g (50 mmol) of 4-nitrophenylhydrazine was suspended in 70 mL ofwater and 10 mL of n-propanol and the suspension was heated to about 50°C. At this temperature, 5 g (50 mmol) of concentrated hydrochloric acidand 4.81 g (50 mmol) of 3-dimethylaminoacrylonitrile were then added.After an additional 15 minutes, 3.8 mL (50 mmol) of a 25% ammoniasolution was added dropwise within 15 minutes. The reaction mixture wasthen allowed to agitate at about 50° C. until the3-dimethylaminoacrylonitrile had completely reacted (about 1 hour) afterwhich the resulting dark-brown suspension was cooled in an ice bath. Theprecipitate was filtered off, washed 3 times with small portions of coldwater and then dried. Yield of crude product: 9.4 g (46 mmol. 92% of thetheoretical).

The resulting crude product was used in Step 11.2 without furtherpurification. A sample crystallized from 1:1 acetonitrile/water foranalytical purposes had a melting point of 166.7° C.

Step 11.2: 5-Amino-1-(4-nitrophenyl)-4-(4-sulfophenylazo)pyrazole

7.79 g (45 mmol) of sulfanilic acid was diazotized, 7.38 g (90 mmol) ofsodium acetate was added, and the reaction mixture was allowed toagitate at 0 to 5° C. for a about 15 more minutes. Then, 9.2 g (45 mmol)of 5-amino-1-(4-nitrophenyl)-1H-pyrazole from Step 11.1 (dissolved in 20mL of dimethyl-formamide) was added dropwise over a period of 30minutes. During the addition, the reaction mixture assumed ayellow-brown color, and an increasingly thick suspension formed. Thesuspension was diluted with about 50 mL of cold water, and the reactionmixture was allowed to stand overnight at room temperature. Theprecipitate was then removed by suction filtration and washed with asmall amount of cold water. The moist, crude product thus obtained(about 14 g) was then suspended in 100 mL of isopropanol, 10 mL (72mmol) of triethylamine was added, and the mixture was heated at reflux.After about 30 minutes, the reaction mixture was cooled slightly, and toit was added dropwise 14.5 mL (112 mmol) of a 25% hydrochloric acidsolution which produced a thick, ocher-yellow suspension. The suspensionwas cooled to 0 to 5° C. and the precipitate was removed by suctionfiltration and washed with a small amount of ethyl acetate. The residuewas dried at 60° C. under vacuum. This gave 12.18 g (31.4 mmol), 69.7%of the theoretical) of5-amino-1-(4-nitrophenyl)-4-(4-sulfophenylazo)pyrazole; melting point:135-136° C. (decomp.).

Step 11.3: 1-(4-Aminophenyl)-4,5-diaminopyrazole sulfate

11.65 g (30 mmol) of5-amino-1-(4-nitrophenyl)-4-(4-sulfophenylazo)pyrazole from Step 11.2was suspended in 140 mL of methanol and then hydrogenated on 0.3 g ofPd/C (10%) at 60° C. at a hydrogen pressure of about 2 bar. Afterapproximately 1 hour, the reaction was complete, and the mixture wascooled to room temperature. The catalyst was filtered off undernitrogen, and the filtrate was allowed to agitate in the presence of22.2 g (about 32 mmol) of Amberlyst A 26 ion exchanger (strongly basic)until sulfanilic acid could no longer be detected in the solution bychromatography. The ion exchanger was then filtered off under nitrogenand washed three times with three 30-mL portions of methanol.Immediately thereafter, the filtrate was added dropwise with agitationat room temperature to a mixture of 3.8 g (39 mmol) of concentratedsulfuric acid and 12 mL of methanol. The resulting suspension wassuction-filtered and the solid was washed with a small amount ofmethanol and dried at 60° C. under vacuum. This gave 6.67 g (23.2 mmol,77.4% of the theoretical) of crude product.

For purification, 1.30 g (4.5 mmol) of the crude product was suspendedin 10 mL of isopropanol and 2.5 mL of water. After addition of 1.4 mL(10 mmol) of triethylamine and heating to about 35° C., the productdissolved and was allowed to agitate in the presence of 0.1 g ofactivated carbon for 15 minutes. The activated carbon was then removedby suction filtration, and to the solution was slowly added 0.3 mL (5.5mmol) of concentrated sulfuric acid which caused formation of a reddishprecipitate. The precipitate was filtered off, washed with a smallamount of isopropanol and dried at 60° C. under vacuum. This gave 1.1 g(3.8 mmol, 85% of the theoretical) of1-(4-aminophenyl-4,5-diaminopyrazole sulfate.

¹H-NMR (DMSO-d₆): δ=3.52 ppm (s very broad, 6H); 5.23 ppm (s very broad,2H); 6.66 ppm (d, ³J_(HH)=14.4 Hz, 2H); 7.10 ppm (d, ³J_(HH)=14.4 Hz,2H); 7.37 ppm (s, 1H).

Elemental analysis: C₉H₁₁N₅×½ H₂SO₄ (mol. wt. =257.69)

C H N S Calculated: 37.64% 4.56% 24.38% 11.14% Found: 37.76% 4.67%24.23% 11.02%

Example 12 Oxidative Hair Colorant, Basic

0.030 g of ascorbic acid 0.40 g of sodium sulfite 10.00 g sodium laurylether sulfate, 28% aqueous solution 7.85 g of ethanol X g of pyrazole offormula (I) as per Table 1 Y g of coupler as per Table 1 9.10 g ofammonia, 25% aqueous solution to 100.00 g demineralized water

Just before use, 100 g of the above dye carrier composition was mixedwith 100 g of a 6% aqueous hydrogen peroxide solution, and the requiredamount of the ready-for-use colorant solution was then applied tobleached hair. After an exposure time of 30 minutes at 40° C., the hairwas washed with a shampoo, rinsed with water and dried. Table 1summarizes the color shades obtained and the L*a*b* values.

TABLE 1 Dye Examples Coupler 2,4-Diamino-1- (2′-hydroxy- N-(3-Dimethyl-5-Amino- ethoxy)benzol. aminophenyl)- m-Aminophenol Resorcinol2-methylphenol 2HCl urea Developer 0.27 g 0.28 g 0.31 g 0.60 g 0.45 gPyrazole red strawberry orange red-violet steel-blue derivative of L:35.6 L: 44.58 L: 48.97 L: 26.34 L: 28.15 formula (l-a) a: 40.33 a: 35.58a: 42.41 a: 39.80 a: 24.36 0.69 g b: 19.57 b: 19.99 b: 44.20 b: 5.28 b:−25.58 Pyrazole red pink- orange red-violet dark-blue derivative ofbrown formula (l-c) L: 32.23 L: 41.69 L: 47.96 L: 24.87 L: 23.15 0.69 ga: 37.59 a: 33.21 a: 45.36 a: 38.59 a: 18.94 b: 18.21 b: 22.90 b: 46.95b: 8.01 b: −15.01 Pyrazole red pink- orange red-violet steel-bluederivative of brown formula (l-b) L: 31.43 L: 31.43 L: 48.51 L: 25.46 L:23.28 0.69 g a: 38.78 a: 38.78 a: 43.70 a: 37.80 a: 18.97 b: 17.43 b:17.43 b: 46.04 b: 7.31 b: −16.52 Pyrazole red pink- orange red-violetsteel-blue derivative of brown formula (l-e) L: 35.99 L: 42.58 L: 50.50L: 28.85 L: 28.81 0.69 g a: 41.85 a: ′33.68 a: 43.31 a: 40.77 a: 25.84b: 18.90 b: 22.52 b: 45.38 b: 6.07 b: −26.12 Pyrazole red strawberryorange red-violet steel-blue derivative of L: 33.55 L: 44.77 L: 49.92 L:27.16 L: 26.14 formula (l-d) a: 41.38 a: 37.69 a: 43.29 a: 39.38 a:24.38 0.69 g b: 17.10 b: 20.17 b: 44.47 b: 4.38 b: −24.96 Pyrazole redred-brown bright red-violet dark blue derivative of orange formula (l-g)L: 34.08 L: 43.71 L: 48.99 L: 27.17 L: 27.39 0.72 g a: 35.64 a: 30.44 a:41.94 a: 36.49 a: 17.32 b: 17.46 b: 24.23 b: 46.00 b: 9.16 b: −13.58Pyrazole red strawberry bright red-violet steel-blue derivative oforange formula (l-f) L: 36.28 L: 42.81 L: 51.56 L: 26.21 L: 30.72 0.69 ga: 41.17 a: 36.66 a: 41.95 a: 39.29 a: 23.82 b: 21.53 b: 23.19 b: 46.56b: 4.31 b: −22.72 Pyrazole red deer- orange- red-violet blue derivativeof brown red formula (l-k) L: 33.71 L: 45.81 L: 49.06 L: 24.32 L: 26.970.64 g a: 32.59 a: 27.99 a: 42.60 a: 35.11 a: 18.22 b: 20.30 b: 27.92 b:47.77 b: 8.67 b: −12.63 Pyrazole- red red bright red-violet bluederivative of orange formula (l-h) L: 31.41 L: 31.43 L: 46.01 L: 24.27L: 22.77 0.69 g a: 39.10 a: 38.78 a: 46.31 a: 37.34 a: 20.25 b: 17.40 b:17.43 b: 45.91 b: 7.44 b: −16.41 Pyrazole red strawberry brilliantred-violet dark blue derivative of orange formula (l-i) L: 30.05 L:40.74 L: 43.46 L: 22.93 L: 23.60 0.72 g a: 38.81 a: 35.42 a: 47.16 a:33.51 a: 18.86 b: 18.26 b: 22.77 b: 42.63 b: 4.02 b: −19.96 Pyrazole redstrawberry brilliant red-violet dark blue derivative of orange formula(l-l) L: 26.91 L: 41.90 L: 39.40 L: 20.79 L: 22.87 0.62 g a: 36.72 a:32.58 a: 48.25 a: 28.40 a: 19.33 b: 14.74 b: 22.41 b: 37.40 b: 5.18 b:−13.53 In material reproduced from the original German document (Tables1, 2), commas denote decimal points - Translator

The L*a*b* color values given in the present example were determinedwith a Minolta Chromameter CR 300 color-measuring instrument. TheL-value stands for brightness (namely the lower the L-value the higheris the color intensity), whereas the a-value is a measure of the redcontent (meaning that the higher the a-value, the higher is the redcontent). The b-value is a measure of the blue content of the color,namely the more negative the b-value the higher is the blue content.

Example 13 Oxidative Hair Colorant in Cream Form, Basic

15.00 g of cetylstearyl alcohol (50/50) 5.00 g of glycerol monostearate2.00 g of Cocamide DEA 10.00 g of sodium lauryl ether sulfate, 28%aqueous solution 0.30 g of ascorbic acid 0.40 g of sodium sulfite X g ofdyes as per Table 2 4.50 g of ammonia, 25% aqueous solution to 100.00 gdemineralized water

Just before use, 100 g of the above dye carrier composition (pH=10 to10.5) was mixed with 100 g of a 6% aqueous hydrogen peroxide solution,and the required amount of the resulting ready-for-use oxidative haircolorant was applied to bleached hair. After an exposure of 30 minutesat 40° C., the hair was washed with a shampoo, rinsed with water anddried. Table 2 summarizes the shades obtained.

TABLE 2 Example Dye 13 a 13 b 13 c 4,5-Diamino-1-(4′-methoxyphenyl)-1.43 g 0.62 g pyrazole.2HCl 4,5-Diamino-1-{4′-isopropylphenyl)- 1.44 g0.65 g pyrazole.2HCl 3-Aminophenol 0.22 g 4-Amino-3-methylphenol 0.09 g0.10 g 5-Amino-2-methylphenol 0.39 g 0.15 g3-Amino-2-chloro-6-methylphenol 0.45 g 0.30 g 1,3-Dihydroxybenzene 0.56g 2-Amino-6-chloro-4-nitrophenol.HCl 0.25 g 0.51 g2-Chloro-6-(ethylamino)-4- 0.05 g 0.10 g nitrophenol1,4-Diamino-2-methylbenzene sulfate 0.31 g1,4-Diamino-2-(2′-hydroxyethyl)- 0.20 g benzene sulfateN-(3-(Dimethylamino)phenyl)urea 0.34 g Shade obtained brilliantbrilliant eggplant + cinder-red red-gold red-violet reflections

Example 14 Oxidative Hair Colorant in Gel Form

15.00 g of oleic acid 3.00 g of glycerol 7.00 g of isopropanol 0.50 g ofascorbic acid 0.40 g of sodium sulfite 0.40 g of sodium hydroxide 10.00g of ammonia, 25% aqueous solution 0.90 g of1-(4-aminophenyl)-4,5-diamino-1H-pyrazole sulfate (1:1) 0.31 g of1,4-diamino-2-methylbenzene sulfate 0.20 g of1,4-diamino-2-(2-hydroxyethyl)benzene sulfate 0.10 g of4-amino-3-methylphenol 0.46 g of 1,3-diamino-4-(2-hydroxyethoxy)benzenedihydrochloride 0.33 g of 5-[(2-hydroxyethyl)amino]-2-methylphenol 0.21g of 3-aminophenol to 100.00 g demineralized water

Just before use, 100 g of the above dye carrier composition (pH=10.8)was mixed with 100 g of a 6% aqueous hydrogen peroxide solution, and therequired amount of the resulting ready-for-use oxidative hair colorantwas applied to 50% gray human hair. After an exposure time of 30 minutesat 40° C., the hair was washed with a shampoo, rinsed with water anddried. The hair color was black with eggplant reflections.

Example 15 Oxidative Hair Colorant in Cream Form, Acidic

15.00 g of cetylstearyl alcohol (50/50) 5.00 g of glycerol monostearate2.00 g of Cocamide DEA 10.00 g of sodium lauryl ether sulfate, 28%aqueous solution 0.30 g of ascorbic acid 0.40 g of sodium sulfite 1.00 gof 4,5-diamino-1-(4-chlorophenyl)pyrazole hemisulfate 0.25 g of5-[(2-hydroxyethyl)amino]-1,3-benzodioxol hydrochloride 0.18 g of3-amino-2-chloro-6-methylphenol 0.22 g of6-amino-3,4-dihydro-2H-1,4-benzoxazine dihydrochloride to 100.00 gdemineralized water

Just before use, 100 g of the above dye carrier composition (adjusted topH=6.6 with 25% ammonia) was mixed with 100 g of a 6% aqueous hydrogenperoxide solution, and the required amount of the resultingready-for-use oxidative hair colorant was applied to different kinds ofhair. After an exposure time of 30 minutes at 40° C., the hair waswashed with a shampoo gentle to colored hair, rinsed with water anddried. The following coloring results were obtained:

-   -   buffalo hair, bleached: egg-plant colors    -   50% gray human hair: egg-plant colors, gray parts fully covered    -   medium-brown human hair: dark egg-plant colors.

Example 16 Oxidative Colorant

0.30 g of ascorbic acid 0.40 g of sodium sulfite 10.00 g of sodiumlauryl ether sulfate, 28% aqueous solution 7.85 g of ethanol 0.72 g of1-(4-aminophenyl)-4,5-diamino-1H-pyrazole sulfate (1:1) 0.31 g of5-amino-2-methylphenol 9.10 g of ammonia, 25% to 100.00 g demineralizedwater

Just before use, 100 g of the above dye carrier composition was mixedwith 100 g of a 6% aqueous hydrogen peroxide solution, and the requiredamount of the resulting ready-for-use oxidative hair colorant wasapplied to bleached buffalo hair corresponding to a more stronglydamaged human hair. After an exposure time of 30 minutes at 40° C., thehair was washed with a shampoo, rinsed with water and dried. Anorange-red coloration was obtained.

Example 17 Oxidative Hair Colorant

15.00 g of cetylstearyl alcohol (50/50) 5.00 g of glycerol monostearate2.00 g of Cocamide DEA 10.00 g of sodium lauryl ether sulfate, 28%aqueous solution 0.30 g of ascorbic acid 0.40 g of sodium sufite 1.38 gof 4,5-diamino-1-(4′-methoxyphenyl)pyrazole.2HCl 0.63 g of5-amino-2-methylphenol 4.50 g of ammonia, 25% aqueous solution to 100.00g demineralized water

Just before use, 100 g of the above dye carrier composition was mixedwith 100 g of a 6% aqueous hydrogen peroxide solution, and the requiredamount of the resulting ready-for-use oxidative hair colorant wasapplied to bleached buffalo hair corresponding to more strongly damagedhuman hair. After an exposure time of 30 minutes at 40° C., the hair waswashed with a shampoo, rinsed with water and dried. A brick-redcoloration was obtained.

Unless otherwise indicated, all percentages given in the present patentapplication are by weight.

1. A N-aryl-4,5-diaminopyrazole of formula I, or a physiologicallycompatible salt thereof with an organic or inorganic acid:

wherein R1 and R2, independently of each other, each denote astraight-chain or branched C₁–C₆-alkyl group, a hydroxyl group, astraight-chain or branched C₁–C₆-monohydroxyalkyl group, astraight-chain or branched C₃–C₆-dihydroxy-alkyl group, a straight-chainor branched C₁–C₆-alkoxy group, a straight-chain or branchedC₁–C₆-hydroxyalkoxy group, a straight-chain or branchedC₃–C₆-dihydroxyalkoxy group, an amino group, a C₁–C₄-monoalkylaminogroup, a di(C₁–C₄)-alkylamino group, a C₁–C₄-aminoalkyl group, a halogenatom, a difluoromethyl group, or a trifluoromethyl group; Y stands for aC—R3 group, wherein C is a carbon atom of the aryl group in the formulaI and R3 is a hydrogen atom, a straight-chain or branchedC₂–C₆-hydroxyalkoxy group, or a straight-chain, or branchedC₂–C₆-alkoxyalkoxy group, or Y stands for a C—H group, R1 denotes ahydrogen atom and R2 denotes an amino group in position 4 of the arylgroup of the formula I; and X denotes an acid radical and n has a valuefrom 0 to
 3. 2. The N-aryl-4,5-diaminopyrazole according to claim 1,wherein (i) R1 and R2, independently of each other, denote a methylgroup, an ethyl group, an isopropyl group, said amino group, or amethoxy group, and Y stands for said C—H group; or (ii) Y stands forsaid C—H group and R1 denotes said hydrogen atom and R2 denotes saidamino group.
 3. The N-aryl-4,5-diaminopyrazole according to claim 1,wherein said salt is a sulfuric acid salt, a hydrochloric acid salt, acitric acid salt, or a tartaric acid salt.
 4. TheN-aryl-4,5-diaminopyrazole according to claim 1, wherein said salt isselected from the group consisting of1-(2,4-dimethylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride,1-(2,5-dimethylphenyl)-4,5-diamino-1H-pyrazole dihydrochloride, and1-(4-aminophenyl)-4,5-diamino-1H-pyrazole sulfate (1:1).
 5. A colorantfor oxidative dyeing of keratin fibers, said colorant containing atleast one N-aryl-4,5-diaminopyrazole of formula (I), or aphysiologically compatible salt thereof with an organic or inorganicacid:

wherein R1 and R2, independently of each other, denote a straight-chainor branched C₁–C₆-alkyl group, a hydroxyl group, a straight-chain orbranched C₁–C₆-monohydroxyalkyl group, a straight-chain or branchedC₃–C₆-dihydroxyalkyl group, a straight-chain or branched C₁–C₆-alkoxygroup, a straight-chain or branched C₁–C₆-hydroxyalkoxy group, astraight-chain or branched C₃–C₆-dihydroxyalkoxy group, an amino group,a C₁–C₄-monoalkylamino group, a di(C₁–C₄)-alkylamino group, aC₁–C₄-aminoalkyl group, a halogen atom, a difluoromethyl group, or atrifluoromethyl group; Y stands for a C—R3 group, wherein C is a carbonatom of the aryl group in the formula I and R3 is a hydrogen atom, astraight-chain or branched C₂–C₆-hydroxyalkoxy group or astraight-chain, or branched C₂–C₆-alkoxyalkoxy group, or Y stands for aC—H group, R1 denotes a hydrogen atom and R2 denotes an amino group inposition 4 of the aryl group of the formula I; and X denotes an acidradical and n has a value from 0 to
 3. 6. The colorant according toclaim 5, containing from 0.005 to 20 weight percent of said at least oneN-aryl-4,5-diaminopyrazole of the formula (I).
 7. The colorant accordingto claim 5, containing additional dye components selected from the groupconsisting of developers, couplers, 4-(2,5-diaminobenzyl-amino)aniline,3-(2,5-diaminobenzylamino)aniline, natural dyes, dyes identical tonatural ones, and synthetic direct dyes.
 8. A ready-to-apply dyeingmixture for oxidative dyeing of keratin fibers, said dyeing mixturecomprising a mixture of a colorant composition for oxidative dyeing ofkeratin fibers with an oxidant in a weight ratio from 5:1 to 1:3;wherein said colorant composition contains at least oneN-aryl-4,5-diaminopyrazole of formula (I), or a physiologicallycompatible salt thereof with an organic or inorganic acid:

wherein R1 and R2, independently of each other, denote a straight-chainor branched C₁–C₆-alkyl group, a hydroxyl group, a straight-chain orbranched C₁–C₆-monohydroxyalkyl group, a straight-chain or branchedC₃–C₆-dihydroxy-alkyl group, a straight-chain or branched C₁–C₆-alkoxygroup, a straight-chain or branched C₁–C₆-hydroxyalkoxy group, astraight-chain or branched C₃–C₆-dihydroxyalkoxy group, an amino group,a C₁–C₄-monoalkylamino group, a di(C₁–C₄)-alkylamino group, aC₁–C₄-aminoalkyl group, a halogen atom, a difluoromethyl group, or atrifluoromethyl group; Y stands for a C-R3 group, wherein C is a carbonatom of the aryl group in the formula I and R3 is a hydrogen atom, astraight-chain or branched C₂–C₆-hydroxyalkoxy group or astraight-chain, or branched C₂–C₆-alkoxyalkoxy group, or Y stands for aC—H group, and R1 denotes a hydrogen atom and R2 denotes an amino groupin position 4 of the aryl group in the formula I; and X denotes an acidradical and n has a value from 0 to
 3. 9. The ready-to-apply dyeingmixture according to claim 8, wherein the ready-to-apply dyeing mixturehas a pH of 3 to
 11. 10. The ready-to-apply dyeing mixture according toclaim 9, consisting of a hair colorant.